Dyeing of polyacrylonitrile fibers



United States Patent Office 2,717,823 Patented Sept. 13, 1955 2,717,323 DYEING F POLYACRYLUNITRILE Frnnns Edmund W. Lowe, Lake Geneva, Wis., assignor to Purdue Research Foundation, Lafayette, Ind., a corporation of Indiana No Drawing. Application January 6, 1951, Serial No. 204,823

4 Claims. (Cl. 8-55) Comparatively recently, a new synthetic material consisting of highly orientated continuous filaments of polyacrylonitrile has been introduced commercially under the trademark Orlon. Continuous filament well as yarns and fabrics made therefrom, has a high dry and wet strength, a high resistance to stretching and a In addition, Orlon dries rapidly and exhibits outstanding resistance to attack by bacteria and Because of these and many other favorable charmediate future. However, continuous filament Orlon, as well as yarns and fabrics made therefrom is highly hydrophobic and is very yarns and fabrics made therefrom, color adsorption by the Orlon is usually zero to very slight. Also contemplated for future commercial production is Orlon staple. Orlon staple, and yarns and fabrics made therefrom, is less difficult to dye than continuous filament Orlon and sents many A number of methods have been suggested for increasas aniline, the cresols, anthranilic acid, resorcinol, phloroglucinol, cyclohexanol, et cetera. These assistants have an appreciable positive eifect with F. Unfortunately, many acetate dyes sublime when subjected to pressure steaming and/or dry heating.

lanthrene Brilliant Blue FFS dry fabriczdye weight ratio was 10:1. The dye bath also contained 1% Duponol as a leveling agent. The dyeing was conducted at the boiling point for a period of two hours.

dye adsorption at the lower pH values. With resorcinol especially a considerable improvement in the levelness of the dyeing was obtained.

n attempt was made to improve the dyeing with Celdye adsorption, with 10% present there was an appreand at 50% dioxane no dye was taken up and the Orlon had the usual corn or cream color of Orlon as commercially produced. (Obviously, when these rimary assistants are present in the dye bath, especially Escape 7 of during the dyeing operation did not occur since all dyeings described herein were run under reflux.)

Dyeings with Eastman Blue 'BNN exhibit a generally P similar pattern to that described in the preceding two paragraphs. Adsorption of dye was slight and the leveltical bleach was obtained.

Celliton Black BA is taken up bycontinuous filament Orlon fabric to give a teal color. The use of phloroglucinol as an assistant results in a bluer and of resorcinol sence of these assistants. The use of ethanol ordioxane as primary assistants gives results generally similar to those described in connection with the two'blue dyes previously considered. With 50% ethanolthe optical bleaching effect was again observed but a few threads in the fabric exhibited a barely perceptible take up of color. With 50% dioxane, the fabric had a very faint overall bluish cast.

Eastone Red B, Eastone Red R, Eastone Rubrine C and Eastone Rubrine R all dye continuous filament Orlon fabric a pale and very uneven pink. In the presence of 20 g. per liter resorcinol in the dye bath, the pink color is largely lost and the fabric is colored a pale pinkishbrown. Eastone Violet BGF hardly colors Orlon and the color adsorption is very uneven, Eastone Blue BGF gives a very pale and very uneven blue. In the presence of resorcinol, Eastone Violet BGF is not adsorbed and Eastone Blue BGF gives a very light gray.

Eastone Yellow 6GN, Eastone Yellow G, Eastone Yellow GN conc., Eastone Fast Yellow GLF, Eastone Yellow RN and Eastone Fast Yellow 4RLF all give pale yellow shades on filament Orlon fiber. On using resorcinol as an assistant, very slightly to slightly deeper shades are obtained with the first three dyes mentioned; with the remaining three dyes resorcinol has no effect.

Eastone Brown 2R colors continuous filament Orlon fabric a very pale and uneven orange; in the presence of resorcinol the color is gray. Eastone Orange 3R gives a pale and uneven orange which becomes brownish when resorcinol is present in the dye bath as an assistant. Eastone Scarlet BG colors continuous filament Orlon fabric a pale and uneven pink; in the presence of resorcinol an old rose results somewhat deeper and less uneven than the color obtained in the absence of the assistant.

Finally, a developed acetate dye (Eastman Black SN) was examined. Obviously, the application of this particular dye necessitated a considerable departure from the previously described basic procedure. This material was applied to the fabric, was diazotized with an excess of nitrous acid and coupled with an excess of phloroglucinol. While this procedure gives a jet black on acetate, on continuous filament Orlon fabric a pale yellow buff was obtained. The use of ethanol or dioxane as primary assistants was decidedly deleterious. Ethanol at low concentrations (2% and in the dye bath) resulted in pale, dirty and uneven colors; at 50%, no color was adsorbed. Low concentrations of dioxane gave dirty and uneven browns and at 50% the dye adsorption was decidedly less than in the absence of dioxane.

The above observations demonstrate that the satisfactory dyeing of continuous filament Orlon is extremely difficult. A large group of conventional acetate dyes (acetates, like Orlon, are hydrophobic) give, at best,

pale shades and, more frequently than not, very uneven dyeings. The use of resorcinol or phloroglucinol as assistants results in some improvement in a few instances but usually these materials have either no effect or a deleterious action. Such primary assistants as ethanol and dioxane have, at best, no action at low concentrations and greatly inhibit or entirely prevent dye adsorption at high concentrations. Due to the many highly desirable properties of Orlon there is no doubt that this synthetic material will come into increasingly wide use in the immediate future and accordingly dyes that can be applied satisfactorily to Orlon would be of great utility and value.

One object of my invention is to provide a class of dyes having a high affinity for synthetic hydrophobic filaments and staples as well as yarns and fabrics made therefrom.

Another object of my invention is to provide a class of dyes having a high affinity for polyacrylonitrile filaments and staples as well as yarns and fabrics made therefrom.

A further object of my invention is to provide an improved method for the dyeing of synthetic hydrophobic filaments and staples, including yarns and fabrics made therefrom.

An additional object of my invention is to provide an improved method for the dyeing of polyacrylonitrile filaments and staples, including yarns and fabrics made therefrom.

Other objects of my invention will become apparent as the description thereof proceeds.

I have discovered that a certain narrow and circumscribed class of monoazo dyes exhibit a comparatively high affinity for continuous filament Orlon including yarns and fabrics made therefrom. As is well known, monoazo dyes are prepared by the reaction (coupling) of a diazotized amine with a suitable coupling component, usually an amine or phenol. I have discovered that if the amine to be diazotized lacks substituents of certain types and if the coupling component carries certain types of substituents in certain configurations a monoazo dye is produced having a high afiinity for Orlon.

In preparing monoazo dyes exhibiting a satisfactory affinity for Orlon, I have discovered that the amine to be diazotized must carry no substituents of a highly hydrophilic nature. The coupling component is an amine or phenol possessing at least one substitueut that is not highly hydrophilic in a position meta to the amino or phenolic group.

Among amines which, when diazotized and coupled with materials conforming to the above criteria, give dyes exhibiting a high affinity for Orlon may be mentioned aniline, p-chloroaniline, p-anisidine, p-nitroaniline, m-aminophenol, m-anisidine, o-anisidine, 4,6-dinitro 2- aminotoluene, 4,6-dinitro Z-aminophenol (picramic acid) and beta (Z-amino 4,6-dinitrophenyl) ethanol.

Among materials which, when coupled with diazotized amines conforming to the above criterion, give dyes exhibiting a high affinity for Orlon may be mentioned mcresol, m-toluidine, resorcinol, rn-phenylenediamine, phloroglucinol (1,3,5-trihydroxy benzene), phloramine (3 ,S-dihydroxyarriline), 3 ,5 -diaminophenol, 1,3 ,5 -triamino benzene and 2,4,6-triamino toluene.

If the amine diazotized carries a strongly hydrophilic group as a substituent, the resulting diazo compound when reacted with a coupling component conforming to the above criteria, produces a dye having little or no affinity for Orlon. Among such amines may be mentioned Z-aminophenol 4-sulfonic acid, 4-chloro Z-amino phenol 6-sulfonic acid, 4-nitro Z-aminophenol 6-sulfonic acid and l-amino Z-naphthol 4-sulfonic acid. Similarly, if an amine with no strongly hydrophilic groups is diazotized and coupled with an amine or phenol carrying a hydrophilic group and/or lacking a non-hydrophilic group positioned meta to the amino or hydroxyl group, again dyes are obtained having little or no affinity for Orlon.

Continuous filament Orlon fabric was dyed with materials prepared in accordance with the teachings of my invention following the basic dyeing procedure previously given.

In most instances, the colors of filament Orlon fabric dyed with a number of dyestuffs prepared in accordance with the teachings of my invention are described below on the basis of the Royal Horticultural Society Colour Chart (RI-IS). In this color chart, the complete spectrum range is divided, in equal gradations, into 64 full hues numbered in spectral sequence from 1 (Sulfur Yellow) through the oranges, reds, blues, greens and finally back to yellow again at 64 (Dresden Yellow).

Each full hue may also appear as a lighter tint of the full hue, indicated by the prefix 6, 5 or 4 added to the full hue designation and separated therefrom by a dash Taking, for example, full hue 7, its relative tint is designated 6-7, its relatively lighter tint 5-7 and its relative still lighter tint 4-7.

In addition, the full hues and tints may be grayed, this being indicated by prefixing one or more zeros to the designation in question. Thus, 06-7 refers to the relative tint of full hue 7 once grayed, 005-7 the relatively lighter tint of full hue 7 twice grayed, et cetera.

Finally, any of the above designations may carry a For one thing, the publication of the chart has not been completed as yet so frequently an exact match of a given sample is not to be found in presently available sections of the chart and occasionally even a reasonably close ap- Aniline:

Phloroglucinol. Red dye produced. On Orlon,

RHS Carrot Red, 6 2 p-Chloroaniline:

Resorcinol. On Orlon, RHS Chinese Yellow, 66/ 1 Phloroglucinol. Red dye produced. On Orlon,

RHS Yellow Ochre, 7/2 Phloramine. On Orlon, RHS Egyptian Buif, 4-7

On Orlon, RHS Yellow o-Anisidine:

Phloroglucinol. Dark red dye produced. On Orlon,

RHS Yellow Ocher, 07/2 m-Anisidine Phloroglucinol. Reddish orange dye formed. On Orlon, RHS, Yellow Ocher, 07/2. (Very slightly deeper shade than o-anisidine-phloroglucinol dyeing, above.) p-Anisidine:

Resorcinol. Brownish gold on Orlon. Phlorogluci- 1101. Purple red dye produced. On Orlon, RHS Egyptian Buflf, 4-7/l 1,3,5-triaminobenzene. On Orlon, oxidized during application.

p-Nitroaniline rn-Cresol. On Orlon, RHS Chinese Yellow, 6-6

m-Toluidine. On Orlon, RHS Mars Orange,

Resorcinol. 0n Orlon, RHS Maize Yellow, 6-7

Phloroglucinol. Dark purple dye formed. On Orlon, RHS Yellow Ochre, 0-7/1 Phloramine. On Orlon, RHS Majolica Yellow,

1,3,5-triaminobenzene. On Orlon, RHS Egyptian Burt, 4- 7/2 4,6-dinitro Z-aminotoluene:

m-Phenylenediamine.

On Orlon, RHS Spanish Orange, 010/2 aniline,

6 Phloroglucinol. On Orlon, RHS Chrome Yellow,

6-5/2 Picramic acid:

Resorcinol Phloroglucinol Phloramine those with phloroglucinol and the triaminobenzene gave relatively lighter and brighter shades. Beta (Z-amino 4,6-dinitrophenyl) ethanol:

Resorcinol. On Orlon, brownish buff. Phloroglucinol. On Orlon, very light buff. Phloramine. On Orlon, RHS Yellow Ocher, 07/ 3. 3,5-diaminophenol. On Orlon, RHS Nasturtium Orange, 6 l0/2. 1,3,5-triaminobenzene.

Orange, 69/ 1.

The use of resorcinol (20 g./l.) as an assistant gave quite variable results. This assistant resulted in slightly deeper shades when used with aniline-phloroglucinol, p-chloro aniline-phloroglucinol, p-nitroaniline-m-cresol, p-nitroaniline-resorcinol, 4,6-dinitro 2 phloroglucinol, picramic acid-resorcinol, 1,3,5-triaminobenzene, beta (Z-amino 4,6-dinitrophenyl) ethanol-phloroglucinol and beta (Z-amino 4,6-dinitrophenyl) ethanol-l,3,5-triaminobenzene dyes. Use of the assistant gave appreciably deeper shades with m-aminoand o-anisidine-phloroglucinol dyes and considerably deeper shades with p-chloroanilinephloramine and p nitroaniline-l,3,5-triaminobenzene dyes.

Use of resorcinol as an assistant gave slightly lighter shades with p-nitroaniline-phloroglucinol, picramic acidresorcinol and picramic acid-phloramine dyes and considerably lighter shades with m-aminophenol-resorcinol, m-aminophenol-3,S-diaminophenol and beta (2-amino 4,6,-dinitrophenyl) ethanol-resorcinol dyes.

Resorcinol as an assistant gave rise to a considerably yellower and brighter dyeing with the p-anisidine-resorcinol dye, a very much darker dyeing with the p-nitroaniline-m-toluidine coupling and a duller and browner shade when employing the p-nitro aniline phloramine dye. With other dyes of the above compilation, the use of resorcinol as an assistant had no visible effect on the dyeings obtained.

Be it remembered, that while my invention has been described by means of numerous examples thereof, these are illustrative and non-limiting and it is to be under- On Orlon, RHS Apricot l. The method of dyeing a material selected from the group consisting of Orlon filaments, staples, yarns and 2. The method of dyeing a material selected from the Orlon filaments, staples, yarns and fabrics comprising treating the Orlon in an aqueous dye consisting of resorcinol and phloroglucinol.

3. The method of dyeing a material selected from the group consisting of Orlon filaments, staples, yarns and fabrics comprising treating the Orlon in an aqueous dye bath containing a monoazo dye formed by coupling a 8 diazotized anisidine with a material selected from the 2,359,735 Kienle Oct. 10, 1944 group consisting of resorcinol and phloroglucinol. 2,424,778 Tainsh July 29, 1947 4. The method of dyeing a material selected from 2,461,612 Olpin Feb. 15, 1949 the group consisting of Orlon filaments, staples, yarns 2,512,969 Richards June 27, 1950 and fabrics comprising treating the Orlon in an aqueous 5 2,532,437 Baker Dec. 5, 1950 dye bath containing a monoazo dye formed by coupling 2,543,316 Feild Feb. 27, 1951 diazotized picramic acid With a material selected from FOREIGN PATENTS the group consisting of resorcinol and phloroglucinol.

568,037 Great Britain Mar. 15, 1945 References Cited in the file of this patent 10 OTHER REFERENCES UNITED STATES PATENTS Amer. Dyestufi Reporter for October 3, 1949, p. P719. 2,141,589 Bishop Dec. 27, 1938 Amer. Dyestuff Reporter for April 22, 1946, p. P194,

2,180,012 McNally Nov. 14, 1939 article by Woodruff. 2,191,040 McNally Feb. 20, 1940 

1. THE METHOD OF DYEING A MATERIAL SELECTED FROM THE GROUP CONSISTING OF ORLON FILAMENTS, STAPLES, YARNS AND FABRICS COMPRISING TREATING THE ORLON IN AN AQUEOUS DYEBATH CONTAINING A MONOAZO DYE FORMED BY COUPLING A DIAZOTIZED AMINE SELECTED FROM THE GROUP CONSISTING OF ANILINE, ANISIDINE AND PICRAMIC ACID WITH A MATERIAL SELECTED FROM THE GROUP CONSISTING OF RESORCINOL AND PHLOROGLUCINOL. 